Small internal combustion engines are used in a wide variety of applications including, for example, lawn mowers, lawn tractors, snow blowers, and power machinery. Frequently, such internal combustion engines employ a device to remove contaminants from the combustion air to prevent premature wear of any internal components. Typically, the contaminants, which mainly comprise air born dirt, sand, cement dust, and chaff from vegetation, are removed from the combustion (or intake) air with a filtering device called an air cleaner. The air cleaner is generally attached upstream of the carburetor or throttle valve on spark ignited engines and upstream of the intake manifold on diesel engines for preventing abrasive particles from entering the engine's cylinders.
To effectively trap contaminants and other abrasive particulate matter, most air cleaners employ a filtering media that performs a filtering operation. Generally, the filtering operation encompasses a sieving process that traps the contaminant particles as they pass through the filtering media. With time, the filtering element, which typically has a finite capacity to trap dirt, becomes restricted as trapped particles build up on and within that filter. Furthermore, as the build up on the filter continues to increase, the air flow continuously becomes more and more restricted until the point when the engine's performance starts being affected. In addition to the continuous build up of debris on the filter, at least some severe conditions can cause the filter to reach its capacity in a short period of time, thereby requiring frequent replacement. Replacing the filter element can be both time consuming and costly for the equipment owner. Thus, it is often desired to employ devices and mechanisms that can provide effective filtering while extending the life of filter elements.
One such device is a pre-cleaning device, which is often employed in conjunction with an air cleaner device to separate out heavier dirt particles from the intake air before that air is provided to the air cleaner. By virtue of utilizing such pre-cleaning devices, the volume of dirt to be removed by the air cleaner filter is reduced. However, utilizing both pre-cleaner and air cleaner devices can significantly increase the footprint of the engine. In addition, they can be expensive devices involving a large number of components that can require considerable maintenance and frequent replacement. Also, many such conventional pre-cleaning and air cleaner devices are not well-suited for allowing efficient engine operation under varying temperature conditions. For example, pre-cleaning and air cleaner devices utilized in engines that are designed for operation under warm (e.g., summer) conditions often are incompatible with optimal operation of the engines under cold (e.g., winter) conditions.
It would therefore be advantageous if an air cleaner device that can effectively trap contaminant particles is developed. It would further be advantageous if such an air cleaner has a smaller footprint and does not require frequent replacing of the filter element. It would additionally be advantageous if such an air cleaner is cost effective to own and maintain. Also, it would be advantageous if, in at least some embodiments, the air cleaner device was compatible with engine usage under various temperatures, such as ambient temperatures, and/or other operational conditions.